Objective • Name and label cell organelles on diagrams and models • List membranous and non-membranous organelles • Match or select from a given list, functions of cell organelles • Describe membrane transport processes • Interpret the role of the transport processes in cell homeostasis in your own words • Sequence and describe the phases of the Cell cycle and Somatic cell division ; match and select from a list with 100% accuracy • Name and label diagrams

Secretion being released from cell by exocytosis Microfilament Chromatin Nuclear envelope Nucleolus Nucleus Plasma membrane Smooth endoplasmic reticulum Cytosol Lysosome Mitochondrion Centrioles Centrosome matrix Rough endoplasmic reticulum Ribosomes Golgi apparatus Microvilli Secretion being released from cell by exocytosis Microfilament Microtubule Intermediate filaments Peroxisome Figure 3.2

Separates intracellular fluids from extracellular fluids Plasma Membrane Separates intracellular fluids from extracellular fluids Contains glycoprotein that provides: Highly specific biological markers These markers function in cells-cell recognition

Fluid Mosaic Model of the Plasma Membrane Double bilayer of lipids With imbedded, dispersed proteins Bilayer lipid consists of: Phospholipids: have (bipoles): hydrophobic tail (fatty acids) hydrophilic head (phosphate-containing) Glycolipids: lipids with bound carbohydrate Cholesterol

Fluid Mosaic Model Figure 3.3

Types of membrane proteins 1- Integral Proteins: Firmly inserted into the bilayer Most are transmembraneous (protrude on both sides) All have both hydrophilic & hydrophobic regions enabling them to interact with: Nonpolar inner lipid tails Water on both sides of the bilayer

Types of membrane proteins 2- Peripheral Proteins: Not embedded in the lipid Losely attached to: Integral proteins, or Membrane lipids Easily removed w/out membrane disruption Include a network of filaments that support the cell membrane from the cytoplasmic side

Functions of Membrane Proteins Transport Enzymatic activity Receptors for signal transduction Figure 3.4.1

Functions of Membrane Proteins Intercellular adhesion Cell-cell recognition Attachment to cytoskeleton and extracellular matrix Figure 3.4.2

Cytoplasm Cytoplasm Material between the plasma membrane and the nucleus. Includes: Cytosol Organelles Inclusions

Cytoplasmic organelles: Cytosol: largely water with dissolved protein, salts, sugars, and other solutes Cytoplasmic organelles: metabolic machinery of the cell Inclusions: chemical substances such as glycosomes (glycogen granules) and pigments

Cytoplasmic Organelles Specialized cellular compartments Membranous organelles: Mitochondria, peroxisomes, lysosomes, endoplasmic reticulum, and Golgi apparatus Nonmembranous organelles: Cytoskeleton, centrioles, and ribosomes

Mitochondria Double membrane structure with shelf-like cristae Provide most of the cell’s ATP via aerobic cellular respiration Contain their own DNA and RNA (self replicate) Known as the “Power-house” of the cell

Ribosomes Granules composed of protein and an RNA (rRNA) Made of two subunits (large and small subunits) Site of protein synthesis Found in two forms: Free ribosomes: Synthesize soluble proteins that function in cytosol Membrane-bound ribosomes: Synthesize proteins to be: Part of the membranes, or Exported from the cell.

Endoplasmic Reticulum (ER) Interconnected tubes and parallel membranes Continuous with the nuclear membrane Two varieties: Rough ER and smooth ER

Rough (ER) External surface studded with ribosomes Its ribosomes manufacture proteins Storage and transport site for newly synthesized protein It is, therefore, called cell’s “membrane factory”

Looping network of tubules communication with rER Smooth ER Looping network of tubules communication with rER Does not participate in protein synthesis Its enzymes catalyze reactions in various organs including : Liver, testes, intestine, kidneys, & muscles In the liver Lipid and cholesterol metabolism Breakdown of glycogen Detoxification of drugs (also in the kidneys)

Stacked and flattened membranous sacs Golgi Apparatus Stacked and flattened membranous sacs Receives ER transport vesicles that fuse at its cis face Modifies, concentrates, and packages proteins into membranous vesicles Delivers processed proteins through its trans face Secretory vesicles leave trans face to 1 of 3 pathways: Release of content from the cell Incorporation into the plasma membrane Formation of lysosomes

Golgi Apparatus Figure 3.20a

Role of the Golgi Apparatus Secretion by exocytosis Extracellular fluid Proteins in cisterna Membrane Vesicle Secretory vesicles Proteins Pathway 1 Golgi apparatus Cisterna Rough ER Figure 3.21

Role of the Golgi Apparatus Secretion by exocytosis Extracellular fluid Plasma membrane Vesicle incorporated into plasma membrane Coatomer coat Proteins in cisterna Membrane Vesicle Pathway 2 Golgi apparatus Cisterna Rough ER Figure 3.21

Role of the Golgi Apparatus Extracellular fluid Plasma membrane Lysosomes containing acid hydrolase enzymes Phagosome Proteins in cisterna Membrane Vesicle Pathway 3 Secretory vesicles Golgi apparatus Cisterna Rough ER Figure 3.21

Role of the Golgi Apparatus Secretion by exocytosis Extracellular fluid Plasma membrane Vesicle incorporated into plasma membrane Coatomer coat Lysosomes containing acid hydrolase enzymes Phagosome Proteins in cisterna Membrane Vesicle Pathway 3 Pathway 2 Secretory vesicles Proteins Pathway 1 Golgi apparatus Cisterna Rough ER Figure 3.21

Lysosomes Spherical membranous bags containing digestive enzymes Perform metabolic functions (glycogen breakdown) Digest ingested bacteria, viruses, and toxins Degrade nonfunctional organelles and nonuseful tissue Breakdown bone to release Ca2+ If leaked can destroy the cell Referred to as “suicide sacs” or “graveyard of the cell”

Membranous sacs containing oxidases and catalases Peroxisomes Membranous sacs containing oxidases and catalases Particularly abundant in liver and kidney cells Oxidases detoxify harmful and toxic substances They convert dangerous free radicals to H2O2 Catalases convert H2O2 to water Free radicals: Highly reactive chemicals with free electrons (O2–) They can scramble structure of biological molecules Normal by-products of cellular metabolism

The “skeleton” of the cell Dynamic, elaborate series of rods Cytoskeleton The “skeleton” of the cell Dynamic, elaborate series of rods Run through the cytosol Consists of: Microtubules Microfilaments Intermediate filaments

Microtubules Dynamic, hollow tubes Made of the spherical protein “tubulin” Determine: Overall cell shape Organelle distribution

Intermediate Micro and Filaments Intermediate fillaments: Tough, insoluble protein fibers With high tensile strength Resist pulling forces on the cell Microfilaments: Dynamic strands of the protein “actin” Attached to the cytoplasmic side of the plasma membrane Braces and strengthens the cell surface

Cytoskeleton Figure 3.24a-b

Centrioles Barrel-shaped organelles Lie perpendicular to each others Located near the nucleus Array of microtubules (9 triplets) Organize mitotic spindle during mitosis Form the bases of cilia and flagella Only sperm cells have flagella

Nucleus Composed of: Control center of the cell Nuclear envelope Nucleoli Chromatin Nucleoplasm (jellylike fluid) Control center of the cell Contains the genetic library Dictates kinds & amounts of proteins synthesized

Selectively permeable double membrane barrier Nuclear Envelope Selectively permeable double membrane barrier Contains pores lined with complex proteins Outer membrane is: Continuous with the rough ER Studded with ribosomes Inner membrane is: Lined with the nuclear protein (maintains nucleus shape) Encloses jellylike fluid called nucleoplasm

Nucleoli Spherical bodies within the nucleus Not membrane bound Typically one or two per nucleus (can be more) Site of ribosome production

Chromatin Threadlike strands composed of: DNA (30%) Histone proteins (60%) Newly formed RNA (10%) When the nucleus starts to divide, it forms: Condensed, barlike bodies called chromosomes Figure 3.29

Chromatin Figure 3.29

Break Silde Biol2401.5039 Sep 12,’12